The present invention relates, in general, to writing instrument mechanisms, and in particular, to a new and useful four part mechanism for extending and retracting a writing point, for example, that of a ball point pen.
Currently, A. T. Cross Company, the assignee of the present application, is manufacturing and selling its very successful ball point pen using an internal 11 to 12 part mechanism. It would be advantageous to reduce the number of parts used to construct a mechanism having the same function while adapting the parts so that they can be assembled in an automated fashion.
A simplified ball point pen mechanism using a reduced number of parts is known from U.S. Pat. No. 2,753,844 invented by Ellery Boss and owned by A. T. Cross Company. The Boss patent, issued on an application filed in 1954, utilized metal parts predominantly and did not have access to modern synthetic materials. The parts of the mechanism were also constructed and shaped for assembly by hand since widespread mechanization did not exist at that time.